Crash with stack trace gz::common::absPath

[gzfuzz]

Environment

• OS Version: Ubuntu 22.04
• Source or binary build?
  source build
  gz-sim version: 5641ef2cc7bed13e06892d29ffd3663b2f172e76
  gz-common version: 1ffd6ef
  built with
  gcc version: 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04)
  build options: -DCMAKE_BUILD_TYPE=Coverage

Description

• Expected behavior: Gazebo doesn't crash
• Actual behavior: Gazebo crashes

Steps to reproduce:

1. run gz sim with any sdf file
2. gz service --timeout 10000 -s /gazebo/resource_paths/resolve --reptype gz.msgs.StringMsg --reqtype gz.msgs.StringMsg --req ''

Output

a.log

[gzfuzz]

https://github.com/gazebosim/gz-common/blob/gz-common5/src/Filesystem.cc#L136

std::string common::absPath(const std::string &_path)
{
  return fs::absolute(_path).string();
}

The root cause seems to be here, no empty check for _path, or shall it be fixed in the gz-sim repository?

https://github.com/gazebosim/gz-sim/blob/gz-sim8/src/ServerPrivate.cc#L489

bool ServerPrivate::ResourcePathsResolveService(
    const msgs::StringMsg &_req,
    msgs::StringMsg &_res)
{
  // Get the request
  std::string req = _req.data();
  // return false for empty req?

  // Handle the case where the request is already a valid path
  if (common::exists(common::absPath(req)))
  {
    _res.set_data(common::absPath(req));
    return true;
  }
  ...
}

[mjcarroll]

Thanks for bringing this up.

It should probably be updated to use the std::error_code variant so that it doesn't crash but instead returns some sort of error, similar to create_directories

gz-common/src/Filesystem.cc

Lines 91 to 99 in 1ffd6ef

	bool common::createDirectories(const std::string &_path)
	{
	std::error_code ec;
	// Disregard return of create_directories, because it may return false if the
	// directory is not actually created (already exists)
	bool created = fs::create_directories(_path, ec);
	(void) created;
	return fsWarn("createDirectories", ec);
	}

[azeey]

@zhileiren are you interested in working on this? Can I assign it to you?

[gzfuzz]

Sure I'm interested. I've not contributed to the gazebo repository before, but if it's appropriate, I would like to try filing a pull request fixing this issue.

[azeey]

Thanks! I've assigned the issue to you. Let me know if you need help with creating the pull request.